In known gas turbine power plants, temperature detecting devices are arranged at the outlet of the combustion chamber to control the temperature reached by the hot gases after the combustion.
The temperature detecting devices used in these plants comprise thermocouples.
However, thermocouples cannot withstand the temperature values reached in the gas turbine plant of the new generation. Thermocouples are made of alloys, for example Pt—Rh alloys, which melt at the operative temperature of the new gas turbine plant.